Disarm and Trip...

[azmodean]

Of course you can get some great slapstick going by tripping them every time they try to pick up the weapon and disarming them every time they stand up.

 

[kjenks]

And after you Disarm your opponent (which could be done as a standard action) you could switch your grip on your weapon to one-handed (a free action) then (using a move action) you can reach 5 ft. into your opponent's square to pick up his weapon. This provokes an AoO on you, but your opponent is unarmed, so he doesn't threaten you and he can't take an AoO.

Now you have both weapons!

 

[deleteaccount]

I could drive my art roleplayers nuts with that slapstick routine .

Another nasty tactic is to have a wizard ready a Shatter spell to be cast at the disarmed weapon.