A few more:
 

BTW: Bring The Wheelchair

ROFL. CGU: Rolling On The Floor Laughing. And Can't Get Up 

OMG: Oy, My Grandchildren!

OMG: Ouch, My Groin!

IMHO: Is My Hearing-Aid On?

WTF: What's Today's Fish?

WTF: Wet The Furniture

IMHMO: In My HMO.

RULKM: Are You Leaving Kids Money?

BYOT: Bring Your Own Teeth

GTG: Gotta Groan

TGIF: Thank Goodness It's Four (Four O'Clock - Early Bird Special)

FWB: Friend With Betablockers

FYI: For Your Indigestion.

JK: Just Kvetching

MILF: Meal I'd Like To Forget

LWO: Lawrence Welk's On

MGAD: My Grandson's A Doctor

SUS: Speak Up, Sonny

WIWYA: When I Was Your Age (my favorite)

GOML: Get Off My Lawn