There are other, very similar ones, but they do not cover the vast frequencies UofT's does.
If you're bummed the University of Twente WebSDR is down but want to listen for SKYKING calls (especially if North Korea goes crazy) and don't like or use Sigmira, GOOD NEWS!
Here's 2 stations that operate similar to WebSDR (same interface).
Select the 30 Meter Band. Type 11175.00 into the frequency and select USB and turn on Squelch. A USSTRATCOM call will be heard, albeit weaker than WebSDR due to distance.
2. Your other choice is http://blerp2.dyndns.org:8901/
Select the 30 Meter band, type 8992.00 in select USB and Squelch.
This one is in Michigan and will receive the signals quite well due to proximity to broadcasts and having a well grounded PA0RDT antenna.
For other frequencies, go to http://www.websdr.org/ and search for what frequency you'd like to listen to to fins an SDR that receives it.