Join Date: Aug 2006
Location: MUC (home), DUS (office), XXX (customer)
Programs: LH, AB, SPG, CC, Sixt, EC
Posts: 6,332
Bruxelles, Belgium
Bonn, former capital of Germany (very close to Cologne, can be done within half day)
Hamburg, Germany (three to four hours by train/car - very worth seeing)
Also out of Cologne, check out the following low cost carriers:
TuiFly and Germanwings are the mayor players but others operate there as well
DUS is the HUB of Air Berlin that has plenty of cheap flights as well, just see what there is