Talking TP. I'm thinking this could be great fun at a party. Record (and re-record) a message, music or sound and then have it automatically play back. The recording device is built into a spindle that fits inside a roll of toilet paper (and fits all holders and toilet paper rolls) so that every time the toilet paper "rolls," the recording is played! Available at the Prank Place.
No kidding! You can advertise your business on TP. No doubt you will have a captive audience. Just Toilet Paper.com imprints your artwork or message on toilet paper for around $2.35 a roll (one color). The minimum order is a little steep though, 5000 rolls. It could take an awfully long time to dispose of 5000 rolls of TP based on Sheryl Crow's suggested TP limitations.
Dirty face soap. Another "just for fun" bathroom item. Looks like real soap until you lather up. The lather turns your hands and face black. Available at Gag Works.
iPod Dock Toilet Paper Holder. No joke, you can now enjoy great tunes from your iPod while "on the throne." Available from Amazon.com. Hmmm, graduations are coming up. Possibly a gift for that niece or nephew heading off to college. Maybe I could even include a few rolls of colored toilet paper from Specialty Toilet Paper.com.