Don your mac and sharpen your wits, because today the Guardian is launching a treasure hunt around two of the most exciting Olympic boroughs, based on a set of clues which you have to solve. Devised exclusively for Guardian Travel by HiddenCity, an online start-up offering urban street hunts across four UK cities, the East End Explorer is an interactive trail through one of the capital's most thriving neighbourhoods – and we have 30 free trails to give away (of which more later). Starting within sight of the Olympic stadium, you will follow a trail of clues through the industrial warehouses of Hackney Wick and the surrounding open spaces to some of the area's most exciting and quirky venues. The "treasure" is the places you discover en route.

You can play in teams of two or four and compete in one team or, "unleash your competitive side" by entering multiple teams. Teams are sent clues (16 in all) via text message. You can see how well you did on the Leaderboard.

Whether you're a visitor, a local, or just someone who relishes a challenge, the Guardian East End Explorer Trail is a great alternative way to explore the area, discovering galleries, cafes and ... well, we don't want to give too much away.

The trail costs £16 for a team of up to four people. Simply log on to inthehiddencity.com/guardian to sign up for the trail. But the Guardian and HiddenCity are giving away free trails to the first 30 readers to sign up on inthehiddencity.com/guardian using the voucher code GUARDIAN101 (terms and conditions apply - see below). Oh – and the mac is not compulsory.

Terms and conditions

1. The HiddenCity / Guardian Trail promotion (the "Promotion") is open to residents of the UK aged 18 and over.

2. Employees of Guardian News & Media Limited ("GNM", "We"), its agencies or its group companies, their family or household members, or anyone else connected with the Promotion may not enter the Promotion.

3. By entering the Promotion you are accepting these Terms and Conditions. Any entry or entrant which does not comply with these Terms and Conditions may be disqualified.

4. To enter the Promotion you must go to the HiddenCity website at inthehiddencity.com/guardian and enter the voucher code "guardian101". If you have any questions about how to enter or in connection with the Promotion, please e-mail us at travel@theguardian.com with "HiddenCity/Guardian Trail promotion" in the subject line.

5. Only one entry per person. Entries on behalf of another person will not be accepted and joint submissions are not allowed. You are responsible for the cost (if any) of entering the Promotion.

6. No responsibility is taken for entries that are lost, delayed, misdirected or incomplete or cannot be delivered or entered for any technical or other reason. Proof of entry is not proof of receipt.

7. The first thirty (30) entrants who correctly enter the voucher code on the HiddenCity website (referred to in paragraph 4 above) by 23.59pm on 27 April 2012 will be notified immediately on the website and will be able to play the Guardian East-End Explorer Trail (the "Trail"). Once you've signed up, the team captain will receive a welcome text message and email with the start location. The hunt kicks off when team captain replies to the text with the word 'start'. Once you've signed up, you have to play within 28 days on any days where the hunt is stated as being available to play. There are no time limits on completing individual clues.

8. The Trail lasts for approximately 3-5 hours. All other expenses not specified in these Terms and Conditions are not included, and are the sole responsibility of the winner, including any travel expenses, food and/or drink.

9. The Promoter's decision will be final and no correspondence will be entered into.

10. Details of the successful entrants can be obtained by sending a stamped addressed envelope to the following address: HiddenCity/Guardian Trail promotion, Guardian News & Media Limited, Kings Place, 90 York Way, London N1 9GU.

11. The Trail is non-exchangeable, non-transferable, and is not redeemable for cash or other prizes and/or gifts.

12. GNM retains the right to substitute the Trail with another prize or free gift of similar value in the event the Trail is not available.

13. Those who are successful in this Promotion may be required for promotional activity.

14. No purchase necessary.

15. Nothing in these terms and conditions shall exclude the liability of GNM for death or personal injury as a result of its negligence, or for fraud or fraudulent misrepresentation.

16. GNM accepts no responsibility for any damage, loss, liabilities, injury or disappointment incurred or suffered by you as a result of entering the Promotion or taking part in the Trail. GNM further disclaims liability for any injury or damage to your or any other person's computer relating to or resulting from participation in or downloading any materials in connection with the Promotion.

17. Entrants' details will be used by GNM and HiddenCity for the purposes of administering the Promotion. Entrants' details will also be used for marketing purposes if You have indicated that you want to receive marketing materials (such as email newsletters) from GNM.

18. GNM may pass entrants' details to third parties where the third party is acting on GNM's behalf for the purposes of administering the Promotion and/or any subsequent publicity, and/or for the purposes of sending you GNM's marketing materials (provided You have indicated that You want to receive any such marketing materials); and/or as otherwise permitted and/or required by law.

19. GNM reserves the right at any time and from time to time to modify or discontinue, temporarily or permanently, this Promotion with or without prior notice due to reasons outside its control (including, without limitation, in the case of anticipated, suspected or actual fraud). The decision of GNM in all matters under its control is final and binding and no correspondence will be entered into.

20. GNM shall not be liable for any failure to comply with its obligations where the failure is caused by something outside its reasonable control. Such circumstances shall include, but not be limited to, weather conditions, fire, flood, hurricane, strike, industrial dispute, war, hostilities, political unrest, riots, civil commotion, inevitable accidents, supervening legislation or any other circumstances amounting to force majeure.

21. The Promotion will be governed by English law.

22. Promoter: Guardian News & Media Limited, Kings Place, 90 York Way, London, N1 9GU.