Wireless Outage

Two nights in a row we have inexplicably lost the wireless network for 45 minutes or so.  No amount of fiddling with channels (the usual solution) brings it back.  There are usually six or so networks that are visibile in the neighborhood at any given time.  None of the other networks are visible when the outage is happening.  The outage affects all of the computers that have wireless networking running on different OSes (Win7, OSX, and Ubuntu).

Is it sunspots at night?

Does someone have gear that is swamping the electromagnetic spectrum in the area?  For 45 minutes+ minutes?