The menu bar items Apple puts in OS X are pretty useful, but you can make them even more so by holding down the Option key when clicking on them. Note that this trick doesn’t work with all menu bar items, just Apple’s (as far as I’ve found. I haven’t tested every app, of course!). Here’s a look at the result of several items with and without an Option-click (note that I’m using Snow Leopard in these screenshots).
The odd thing is there’s a difference in the Time Machine menu, too, but OS X won’t let me take a screenshot of the Option-click version. When you Option-click, Back Up Now turns into Verify Backups, and Enter Time Machine becomes Browse Other Time Machine Discs.