I was thinking of getting a dating sim game for my boyfriend (I'm curious about it to), but I was wondering if anyone has played them. If so, what are they like and can you recommend any good ones?

What do you mean by that? Thanks to boneheaded American publishers misapplying the term, "dating sim" can refer to two very different genres of game:

• Actual dating simulations with stat building and all that jazz, which were briefly popular back in the '90s but aren't that common anymore - I think the only one published over here was True Love, and not sure if any successful fan translations were done.
• Ren'ai games, which have no simulation aspects, are more like interactive novels and significantly more popular both in the East and the West.

Anyway, see the other thread: http://4-ch.net/games/kareha.pl/1105242533/

I can recommend Yuugeki Keikan Patvessel by May-Be Soft, assuming your boyfriend can read Japanese. If not, I suggest Tokimeki Check-In by Crowd, which is available through jastusa.com if memory serves me rightly.

Hourglass of Summer is surprisingly decent if you're after a story-based thing.

Can't give the US translators much credit though as they have dropped meanings of several words (normal for US translations) but also added heaps of grammar and basic spelling errors. It's good enough to get by I suppose, and you can always tune out what you're reading and just go on the voices...