In career mode, you have the option of taking on a number of altitude record contracts, which are simply to get a rocket to a given altitude. However they're presented one at a time, and if you pass the record for the next contract, you won't be offered it; instead you'll get the one after that. While this might not seem like a big deal, it means potentially missing out on funds, science, and reputation early in the game, generally when you need it the most, especially when playing on hard mode.
So what are the various altitudes for which I can get an altitude record contract?