SiliconEra has the most detailed gameplay info I've seen so far (not that I've been looking!) for D3's WTF for PSP, which we've previously covered in-depth under Japanese title Baito Hell 2000.

Among the mini-games: "In Private Number players take a stab and guessing a girl’s phone number out of the blue. When the game starts her profile tells what she likes and the four numbers used in her phone number. If you’re on the right the track she will give you signs like “Bingo” or act surprised. If you have the right number, but in the wrong place she’ll give a different sign. The faster you guess her number the more money you’ll earn. Also after you guess her number you can “call” the girl."

Also, uhh, 'Restaurant Bill Splitter': "One of the most useful tools in WTF, the restaurant bill splitter asks for the amount of money on the check and how many in the party to split the bill with. Then it divides the bill evenly or you can set it in “gentleman mode” so all the ladies pay less for the meal." Yes, this game is crazy - and reportedly not actually that great.