desert v. dessert

A desert (with one ‘s’) is an often sandy region that receives very little precipitation.

A dessert (with two ‘s’s (or ‘esses’, if that’s clearer)) is a usually sweet course served at the end of a meal.

Also of note: The word desert (spelt like the first word above, but pronounced like the second), as in the phrase ‘just deserts’, means ‘something that is deserved’.

Mnemonic devices on eHow.com

Snopes.com on ‘just deserts’