Here's a great idea from Social Selling/LinkedIn guru, Kurt Shaver.
In LinkedIn, enter a city name in the search form, where a team from that city is participating in a big game. On the results page, click the People tab. Then click on the "1st" box to limit results to just first-level connections. Then reach out to those connections with a congratulatory note. You'll almost always get a response, and it's a great way to engage with prospects and clients in a way that is relevant to what they care about.