foursquare:

overkill:

1. Login to your foursquare from your web browser
2. Go to foursquare feeds
3. Copy the link (URL) for the the ICS feed
4. Open iCal’s menu -> Calendar -> Subscribe…
5. Paste the ICS URL you copied from foursquare feeds
6. Click Subscribe in iCal
7. Adjust the Auto-refresh value to your liking then click OK