Here's a fun Alt-Tab Shortcut that lets you switch apps without leaving the comfort of your mouse.  Just download, place in Startup, and run.  When it's running, you can switch apps by holding down the left mouse button and clicking the right.   Like most productivity apps, I may find myself forgetting it's there and not using it after the novelty wears off, but I guess we'll see.

Incidentally, the standalone exe is a feature of AutoHotKeys, which is one of those said productivity apps that I forget about and rarely use.  The idea is pretty neat though. It's a little scripting language for automating those little repetitive tasks that we all hate.  The end result is apparently a standalone exe that "just works", no installer required.