not to offend, but dont waterbeds seem a little 70's-ish? lol.
agreed with not going below... just tell them to find a fixed point on the horizon and look at it... also ive found that bitters and ginger ale seem to help:
Angostura bitters - Wikipedia, the free encyclopedia
oppps.... gotta go
How inappropriate to call this planet Earth when it is quite clearly Ocean ~ Arthur C. Clarke