Watch the Day 17 online guitar lesson by Ravi from Learn Guitar in 21 Days
Okay, let's expand your repertoire a little further. Pick a couple of tunes that you can hum in your head but haven't tried before.
Remember, listen to a sample mp3 online (such as on Amazon) if you need a little reminder of how a song sounds. Then, try to sing and play it.
Today might be a good day to try two new three-chord songs and maybe a four chord song that mixes majors and minors. Look through the list and see what strikes your fancy.
Ultimately the choice is yours, but please spend the time today breaking new ground on songs that you haven't tried before.