FreeKey, despite its unfortunate-sounding name, is a rather neat keyring that makes it super easy to add or remove keys, and keeps them secure the rest of the time. All you have to do is press in on the section that sticks out a bit, which opens the "end" of the keyring for easy access.

See how it works here:

If you find yourself having to remove keys from your ring often, and want to save yourself a bit of hassle (and possibly a broken nail), you'll dig FreeKey. A single ring is less than $6 on Amazon, and they offer packs of two ($13), three ($18), five ($29), and ten ($57) if you need more.