There is very little along the way between LA and Vegas. As someone else mentioned, the World’s Largest Thermometer but I dont think that exactly falls into the "fun" category. Here are a few other choices…

There is a farly large Outlet Center in Barstow if you are in the mood to do some shopping. It has about 25 different stores.
http://www.barstowoutlet.com/

I dont know how much time you are looking to spend but the 15 runs along the north edge of the Mohave National Preserve. About 30 or so miles south of Baker is the Visitor Center. If you are into nature, its supposedly very beautiful in a desolate sort of way. Just keep in mind that this time of year it is just brutally hot out there so be very prepared. Here is a link to the web site…

http://www.nps.gov/moja

If you are looking for something a little quicker and less off the beaten path, the only other fun thing I can think of would be the Despardo roller coaster and a few other amusement rides at Buffalo Bill’s Casino in Primm (Stateline.)
http://www.primmvalleyresorts......tions.html

For info on all of the casinos and hotels once you get to Vegas check out…
http://www.LVCasinoInfo.com

I hope this has helped and have a great trip!

there is only one thing you will be doing…..enjoying the air conditioner…trust me on this one…its all desert.Also you might want to switch drivers every now and then to avoid getting a sunburn on one arm.The worlds tallest thermometer is located in Baker,CA..it is 134 ft tall.It is digital and will help you determine how long you will survive if your car breaks down or the air conditioner breaks.This drive you are planning will feel like "a trip to hell"….try to keep your chipper attitude.

Play games in the car, stop by that thermometer thing, bring mini fans. It will be scorching. Im going on sunday it will be 100+ degrees.

Found the best thing to do is what my daughter use to do when we drove it. She slept. Boring boring boring. Bring a book or portable DVD and watch a couple of movies.

When you drive through Primm, there’s a nice outlet mall and Wild Bill’s. At Wild Bill’s, they have a roller coaster and kids game area (the roller coaster is similar to the one at New York New York).