A sonic screwdriver? All right, that's a new one on me. Gallifreyan too. Looks like I'll be learning all kinds of new things here.
Space and time travel. The latter's still on the rough side, but as soon as I realized I didn't need to compensate consciousness over physical matter as much as I did last time - well, let's just say I'm glad I didn't revert in age any more after my last attempt to go back in time.