I was watching Robin Williams promoting his Broadway CD and DVD on the
Late Show with David Letterman, and it reminded me that Williams can
actually be funny when he’s not acting in crappy films.

A few years back Williams won an award on TV (not the Oscars), and his
acceptance speech went off on tangents everywhere. The only bit I
remember is when he did an impression of Mother Theresa with his fist.

It was so funny that Dan Ackroyd, who might have been the host,
announced that Williams had won another award that was completely
made-up, just as an excuse to get Williams back onstage.

He did, and ended his second speech with the words, "This award is
really insignificant."

I want to see these acceptance speeches again.

Where did they take place and how can i get a copy?

I haven't been able to track down a transcript, but I wonder whether
the occasion may have been the 55th Annual Golden Globes Awards
ceremony. Robin did quite a bit of ad-libbing to cover for the absence
of Christine Lahti:

"When the award for best actress in a television drama series was
announced, winner Christine Lahti (Chicago Hope) was nowhere to be
found. A man (her husband?) took the stage and stalled, hoping she
would return from the ladies' room momentarily. When a few uneventful
seconds passed, Robin Williams (dangerously seated right next to the
stage) jumped up and ad-libbed, passing the time as only he can do
until Miss Lahti's arrival. Lahti accepted both the award and a hand
towel which Williams managed to pull out of thin air."

http://www.moviereel.com/gg9798.html