I just Joined moddb.
Because of the hl2 mod Dual Reality. If you haven't already checked this out, do it now.
I also joined for a couple of other cool mods, including:
City 17 Episode 1
Tales of Galactopticon
and... something else.
Dual reality is a cool mod where the player can shift between realities, which creates for puzzles even more inovative than portal. (hopefully)
City 17 Episode 1 is a mod set during episode 1, but it has HUGE engine improvements.
Tales of Galactopticon is a comedy sci-fi mod, where you play as an alien and looks pretty cool so far.
Raindrop... Well, I haven't been looking at raindrop too much but it looks pretty cool.
Ah yes, the last mod, I can't remember it's name looks really cool as well.
Oh, its called visage.
So look up those mods And start preparing for some fun...