While knife throwing remains popular among travelling magicians and carnival spouses, ice skating is America's number-one bladed activity. For $10, today's Groupon gets you a skate rental and admission to general ice skating at Sky Rink at Chelsea Piers (up to a $21.50 value).

The facilities at Sky Rink at Chelsea Piers are clean and well maintained, and the indoor twin rinks offer a wintery reprieve to sun-shunners of all ages. The location on Pier 61 boasts amazing views over the Jersey Separator, aka Hudson River, providing a soothing backdrop for triple lutzing, double axeling, and single honey-baked hamming. Since the general-skating sessions are available all summer, fans of juxtaposition will get a kick out of the temperature difference between the ice beneath and the sunny sky above. Though not valid with your Groupon, Sky Rink also offers ice-skating and ice-hockey camps for extra-icy fun throughout the summer. Skating provides an opportunity to impress a date by showing off Olympic-quality moves or challenge a bitter rival to a staring contest on ice. The rink is open for general skating on Monday and Friday from 1:30 p.m. to 5:20 p.m., Tuesday and Thursday from 3 p.m. to 5:20 p.m., and Saturday and Sunday from 1 p.m. to 3:50 p.m. Check the online schedule for any seasonal schedule changes.