The D Augmented chord, can also be written as D+ and here is played together with a regular open D major chord. The augmented adds dissonance and tension.
D augmented can also be written as D major #5, D+
D augmented uses these notes D, F#, A#
Augmented chords are constructed from the root, 3 and #5. Augmented chords aren't used anywhere near as often as regular major and minor chords, however if you're looking to add a little tension to your music try throwing in an augmented guitar chord next time you're writing a song.