Marijuana for sure. I could argue for all drugs, but I understand the apprehension about that.
Also all marriages between two consenting adults.
And I would make it highly illegal to use any form of bias (race, gender [ transphobic or sexist in nature], sexual identity, etc.) for important things.
Driving without a license (for those who have a license). I don't know if it varies per state, but, in Georgia,if you have your license and for some reason you forget them or don't have them on you while you're driving you still get written a ticket when they can just look it up in there little system and clearly see that you are a licensed driver. I mean I never forget mine anyway because I always make sure I have ID on me in case of emergency, but my friend got in trouble for that it the other day because she lost her wallet.
marihuana, prostitution, euthenasia, abortion, gay marriage