For anyone who likes roleplaying, there are loads and loads of good mods for Neverwinter Nights 1. There are also a few out for Neverwinter Nights 2 (though none that interest me personally as of yet). This site has most of them.
http://nwvault.ign.com/
There is an upcoming mod trilogy for Neverwinter Nights 2 that really looks spectacular. This team really set the bar high when it comes to delivering a unique experience. They have loads of custom stuff, including voiceactors, music etc. How it will turn out, I don't know, but it certainly looks interesting.
The first part is due to come out in late summer I think.
http://www.roguedao.com/
Jam it back in, in the dark.