From Thinkgeek:

Enjoy World 2-2 while you’re underwater in the shower or tub with this Nintendo Super Mario Shower Curtain. Complete with Cheep Cheeps and Bloopers, this shower curtain comes preloaded with its own hazards. Just remember that slipping and falling in the bathroom is the real hazard, and no Power Up will protect you from that.

[Nintendo Super Mario Shower Curtain]