So I recently started playing Fallout 3 and
I was wondering if there are any casinos in Fallout 3? I really liked playing slots and blackjack in NV and wanted to play it in 3.

Unfortunately not. I did use a mod once on PC that put a non-working casino in Megaton. Not sure if somebody has built a proper one.

You could always try your hand at Red Dead Redemption...

I made a http://www.nexusmods.com/fallout3/mods/13143 mod for Moriarty's, it's fully animated and works in real time unlike the slot machines in NV. Was working on a roulette mod too but I had to abandon it before going completely insane .

Beware of the triple skulls (it's a Space Quest 1 reference).