This one never gets old

[Spriggan]

bathroom break

bearskin rug bathroom

birthday bash

[Entsuropi]

I have hung on IRC a lot and i have NEVER seen those meanings. You been talking to random AOL users? Don't, they are the homeless vagrants of the internet.

And birthday bash would be abbreviated to BDB i would think.

[stacer]

Sprig--I talked to Evan today and he said he knew you and that he would run into you from time to time at BYU.  He's my neighbor (well, relatively--he lives a 10-minute walk away, in my neighborhood) and his school is right next door to mine, so we run into each other a lot. He's also the cousin of a friend of mine, which friend was the roommate of a girl who was my neighbor at BYU, whose brother married my old roommate. Fun. I love how small a world it always is.

[The Holy Saint, Grand High Poobah, Master of Monkeys, Ehlers]

Yeah, I haven't seen any of those usages. Though I'd believe Bathroom break, which amounts to the same thing as Be Right Back.

[Spriggan]

Bathroom break is used in games like warcraft, diablo and MMORPG.  I made the other two up for the fun of it.  Anther that has different menings with the same abbreviation is GTG

which can be good to go or got to go.  That causes problems.