stuff I like: BoWrench
It's not often that I get excited about a new tool - after all, while new and useful gadgets do appear on the market from time to time, the old standbys of saw, hammer, screwdriver, pliers and wrench seem to be working just fine for awhile now. Advertised as a decking wrench, this untique $40 tool would be good in many other applications as well, including subfloor & fencing installation.
The Cepco BW-2 "BoWrench Decking Tool" is basically a clamping lever (that fits onto a joist) that allows you to straighten long boards and holds them so that they can be nailed into place. It'll join tongue & groove pieces, can push and pull, and will close gaps as much as 2 inches.