Details for the 2014 edition of this unsupported ultra-long-distance across Europe are starting to be announced. Like this year's inaugural Transcontinental Race, the 2014 version will start in London and end in Istanbul about 3000-3500 km (2000 miles) later. Apart from one or more checkpoints along the way, riders plan their own routes. The time limit to record an official finish was 15 days last year, with the winner only taking half of that. Here's a brief video of the highlights of the 2013 edition.
Only about 30 people signed up for the ride this year, with a maximum of 100 allowed; but only about 23 finished (and some didn't get an official finish time due to missing one of the two controls or the time cut-off). It received quite a lot of press coverage before during and after (e.g., road.cc ran several articles, including this one), so more people should know about it this year and they should have more entries. Entries for the 2014 edition will open at 8pm (UK, GMT) November 25th, 2013.
Apparently the entry fee last year was a miniscule 95 euros, which coupled with the fact that support vehicles and all other forms of support are not allowed makes this a VERY affordable event. All you need to be able to afford is the time, and my boss has already promised me that I can take vacation then . The start date will be August 9th (Saturday), 2014, in London (Westminster Bridge).
They are ready to announce where the intermediate control will be for 2014, but they first want to reach 2,014 "Likes" on their Facebook page before announcing it. They're currently only about 20 Likes away from that, so head on over and click the counter if you have a Facebook account.
The Transcontinental Race website is currently down while they add all the updated details for the 2014 edition, but hopefully it will be operational soon. You can still see the routes taken by the 2013 participants based on their satellite tracking data here; click on 'Map Layers', then 'All Rider Tracks' to see the routes, and click on 'Start Replay' at the bottom for an animation of how the race progressed.