FANTASTIC 2D examples Garrett!
For 3d...
I would suggest buying a WS edition and a Pan N Scan edition of a DVD. Don't unwrap the P+S so you can return it for a refund afterwords
Other ideas - popcorn. Remote control.
Or just go for the completely different - out of bounds -
Bring in a GI Joe - "Thi is VHS on a 25" Screen in momo'
Then open the door for a fully decked out soldier waiting outside.
This is home theater!"
Or even better, a barbie and a bikini model! (Or just an attractive blonde in an outfit matching barbie)
Or, get one balloon filled with helium and another with helium and hydrogen (experement to find the right - and safe - mix) Hold out the helium one labled "VHS" and hold a match to it. Then the other call it "Home theater" and light it up for a great reaction from the audience!
I could go on and on....