Watch the Syncopated Rhythms online guitar lesson by Angus Clark from Hard Rock Survival Guide: Rhythm
Most of these lessons may seem pretty simple, but we're actually building up a diverse skill set. Now I'm going to add some real rhythm exercises to the mix. One of the first easy songs people learn is "Sunshine of Your Love", and they usually sound terrible playing it because while the notes are fairly straightforward pentatonic, the rhythm is on the off-beats, or is syncopated. Syncopated rhythms are a big part of hard rock, now more than ever, as Math Rock bands have started using syncopated groupings to push phrases over the bar line. There are a couple of chording exercises here, and then a big pentatonic scale exercise. I've included this because so much hard rock rhythm playing is pentatonic-riff based, so you need to have the pentatonic scale pretty well mastered. I approach it a bit differently than most textbooks in that I prefer to slide through fingerings, it's more the way I actually use it, so check it out, you'll be glad you did.