I'd ask for a gadget-making gadget. Sort of like a Coke machine, except gadget-dispensing and programmable so that I could make my time-pausing devise, or my dimension-seeing device, or a really nice stereo, as needed.
On the other hand, that whole "Wish on the Monkey's Paw for more wishes" thing didn't work out so well for me, so maybe it's a terrible idea.
JBS Haldane's Four Stages of Scientific Theories:
1. This is worthless nonsense.
2. This is an interesting, but perverse, point of view.
3. This is true, but quite unimportant.
4. I always said so.
A door that is accessible anywhere at any time that opens across space and time to any location in the world...the only stipulation is that I need to have seen the "opening point" either in real life or an image for it to be able to open there.
Kind of like the motel key for room #10 in the sci-fi miniseries "The Lost Room."