Okay, well we're at simple shit...
here's a simple bass+drum loop with the Bass going from A to E.
Try this over it...
Over everything you can-depending on how you look at it-either play C major, making the progression Am to Em
G major making it Am to Em
D major making it A7 to Em
Amajor making it A to E7
of course A minor and major pentatonic as well as Eminor pentatonic or a mix of all the above will work just fine.
Just remember to play to how the bass changes, in other words don't ride the A note over the E, unless that's what you really want.
Here's the loop...
http://www.eddegenaro.com/theory/atoe.mp3
And with a quickie wank...
http://www.eddegenaro.com/theory/atoe2.mp3