I'm making a HL:SP Mini Mod. I have made about 15-20%.
Ok, the idea:
You play as g-man. You must make sure gordon freeman doesn't die.
You will be following him around, removing traps , opening doors etc etc.
Some screens:
http://crazymoocow.net/dawn1.jpg
http://crazymoocow.net/dawn2.jpg
http://crazymoocow.net/dawn3.jpg
You like the idea?
(and yeah, why not hl2 bla bla bla)
(and yes, that box is the g-man briefcase ;))