I'll post a few...

  (Edited: )

I'll throw a couple out there and see what you think if you ever see this.

1) Mother Knows Best: You can only attack in conjunction with a Mothership Core or a Mothership. If it dies in the battle, you must immediately retreat.
2) Chivalrous Braggart: You must publicly state every time you expand, attack, or drop. If your opponent attacks you, immediately following fending it off, assuming you do, you must talk smack to him. Politely, of course.
3) Low Gas/Brood War Style: You may only have one Extractor/Refinery/Assimilator per base.
4) Not Enough Energy: You may only build units that have energy. (Queens, Ravens, Infestors, Oracles, Mothership Cores, Ghosts, Motherships, High Templar, Sentries, Medivacs, Battlecruisers, and Banshees. If I forgot one, sorry.)
5) You Must Construct Additional Pylons: You may only build Pylons, Supply Depots, and Overlords when supply blocked, and may only build one at a time.
6) Divide and Conquer: In a team game, you and your allies must publicly state one person who they and you will attack, and then may only attack (or defend against) that person, until that person is dead or has left, at which point you'll pick another player. If your ally dies, you cannot attack the person they were targeting until you've killed your player. More than one person may select the same enemy player.
7) One Piece At A Time: In a FFA game, you must publicly state one person who you will attack, similar to #6. You may then only attack that player until they're defeated, at which point you may pick another player. If the other players attack you, you may defend.
8) Uber Units: Before attacking with any units, they must be at least 1/1 in upgrades. For Protoss, they have the choice +1 Attack/+1 Armor or +1 Shields. If the units have separate upgrades for their type, then those must be 1/1 as well. (Ex. Terran Mech units have separate upgrades than Infantry units. Those must be 1/1 before attacking. The same applies to all air units.)
9) Mindset Swap: Any attacks must be executed with buildings, and any defense must be executed with units.
10) Attrition: You may not have any more than two bases at a time.