I was wondering if there is somewhere I can download the open gamespy sdk. They seem to have discontinued it a while ago and the gamespy servers are being shutdown soon as well... Though I still need it but can't seem to find it anywhere.

The Gamespy SDK was never released publicly. However, the Gamespy protocol is actually quite simple. You could probably reverse engineer most of it in a few evenings. You can also look to the communities of games that relied on Gamespy for their multiplayer. Everything from work arounds to alternative implementations of the Gamespy servers are available for these games. To my knowledge the Gamespy protocol should be the same across games though maybe older games are using an older version of the protocol.

Try Neverwinter Nights. It has a fairly active community, and they are using a community created Gamespy service that is open source if I recall correctly.