Random noises

I keep hearing random sweeping noises... I cannot figure out what is causing them or what it is causing them... It looks like Safari is open, Ichat is open, iTunes is open, Preview is open, 2 pages documents are open and a keynote file is open... There doesn't appear to be any changes in anything when I hear it... I'm not receiving an im ... anyone have any ideas? I just heard it 2 or 3 more times while typing this.

It's not Entourage checking mail?

hmmm... I don't think I am familiar with the Entourage application...

Sounds like you don't have Entourage. It's a Microsoft application - Outlook equivalent for mac.
Are the noises coming from the speakers? Turn them off and check to be sure.
Could be a hardware noise?

Oh no... I'm positive it's from the speakers, it's an animated wooooosh noise haven't heard it in a couple of days though