This has happened to me a lot more than I’d like to admit: I’d be browsing around with about a million tabs open, and for some reason I would decide that closing some of them would be a good idea.
Not so much.
As it turns out, I actually needed that last tab, but instead of cursing and throwing a fit of lament, I remembered this handy key combination.
Just click Ctrl+Shift+T and your last closed tab will open up!
This works in Mozilla Firefox, Google Chrome and Internet Explorer! Give it a try next time you accidentally close a tab you needed!