I just bought a couple of those tennis racquet thingies for zapping flying bugs - powered by 2 AA batts [don't touch the grid - it gives a helluva belt!]. You press a button to activate, and is supposed to be effective indoors and out [I wasn't about to sit out in the rain yesterday to check it out!]. Cost about £6 from my local garden centre.
I've also heard that chestnuts spread liberally around the room [behind furniture, in the corners, etc], are very effective as a spider deterrent - waiting for the blighters to fall off the trees and then I'll try it. Also supposed to be good against moth grubs in woollen clothing...