^exactly right.
Look through the posts on Jalopnik that Murilee does with the full photo array from each of the Houston races, then go and find a car that hasn't raced there before. Then come up with a good theme, but if you have a really unique crapheap, the theme is less important.
The downside of this is that if your team isn't already very mechanically inclined, it might make it tougher to run the race. But a short list of vehicles to consider would be: anything pre-1960; especially obscure vehicles like European-only stuff that has been abandoned on our shores; Communist bloc cars; Triumph Spitfire (seriously); a Datsun 1600 roadster would probably be welcomed with open arms.
Use crazedlist.org to search multiple craigslist cities and limit your search to cars between $2 and $1000, then find some obscure crapheaps. Keep an eye open on this forum in the Cars for Sale section, there are plenty of folks here who get bored at work and cruise craigslist looking for interesting Lemons cars and then they post those up here.
Whatever you do, don't announce that you have some crazy car and are starting your build and then don't make the race. That's lame. Better to come in stealthy and amaze everyone at the track than talk big and not show up. Talk is cheap.
Bring your questions on as you have them, this forum is (mostly) very helpful and especially flame free in the Newb forum. But do yourself a favor and use the "search" function first, stuff like what tires to use and how to wire a kill switch have been well covered already and you'll save yourself some hassle by looking them up first. Good luck!
Pat Mulry, TARP Racing #67
Mandatory disclaimer: all opinions expressed are mine alone & not those of 24HOL, its mgmt, sponsors, etc.