A group of us took part in the Scum Run rally this year - looks like a similar idea to the one above.
http://www.scumrun.com/index.php
The idea is all entrants have a car worth under £500 on the day of purchase. After that you can do what you want to it! Our car was an old Subaru. One of the lads works for a sign company, he provided all the vinayl for the car including the decals. The organiser of our group had a mate making some sort of race car who provided a (damaged) rear spoiler which is artfully (and "safely") attached to the roof using two wall mounted bike hooks.
Car almost complete - just missing final sponsor decals
The lads landed in Europe
Unfortunately I currently live in Dublin and the rally took off in the UK. I was due to travel over to the uk on the morning of the first day, however, the icelandic volcano had other ideas. So rather than taking off on the rally I skulked back in to work to much laughter.
However, the lads had a cracking time (apart from a shredded wheel on the M25 before the Run even started)
This years route took them up through Europe including an evening in Amsterdam (I'm told they rolled into their tents at about 5.30, back up at 9) and even a visit to the Ring (which i think has to be the part i was most dissapointed to have missed!)
It's an anual thing for charity but they also do a Rag The Ring expedition, no restrictions on cars, just a bunch of enthusiasts on a road trip to the Ring