Because every Doctor Who fan needs a TARDIS shower curtain! It comes from ThinkGeek and can be yours for only $30.
If you've always wanted to step inside the TARDIS, here's your chance. This 72" square shower curtain will let you get away from the craziness of the real world, if just for a few minutes. (It works best if you actually take a shower. If you just stand in there, people tend to ask questions.) But when you step inside, you'll be able to transcend time and space... at least until the hot water runs out. However, if the control room is overrun with mildew, that's your problem.
And yes, she took that Sonic Screwdriver in the shower with her.