I just launched an Android App that can be used to create, promote, and invite your friends to your team's watch parties and tailgates. The Fan Map App on the Google Play Store is a free download. An iPhone App will be released soon as well.
Also feel free to check out our site as well at FanMap.com. The premise of the site to introduce you to fans that live in your area and follow the same teams as you. It shows where your fans meet and ultimately grows your fanbase in your area. This is perfect for alumni groups.
Thanks in advance for any feedback. I live for college sports, and hopefully this app can help sports fans get more organized on gameday.