Though canines love tennis for its bouncy yellow balls, humans appreciate the freedom to bark loudly with each swing and bury their favorite rackets all over the court. Help sharpen your beastly skills with today's Groupon: for $25, you get a re-stringing (up to a $39.99 value) and re-gripping (a $10.49 value) for one racquet from Boston Ski + Tennis in Newton (up to a $50.48 total value).

Boston Ski + Tennis’s knowledgeable staff will revitalize tennis racquets with a crosshatched chorus line of high-end synthetic strings during a racquet re-stringing, which helps improve a racquet's responsiveness and is a necessary part of regular care and upkeep. Groupon holders can choose from this collection of brand name strings: Babolat RPM, Wilson NXT, Gamma Live Wire, Luxilon Big Banger, Dunlop Silk, Prince Premier, and Head FiberGel. Next, Boston Ski + Tennis will strip racquets of sweaty and preexisting grips in favor of a premium Wilson or Head grip, which will keep racquets from flying out of players' hands when they're hammering vicious backhands or waving to low-flying helicopter pilots. Customers do not need to make an appointment and drop-ins are welcome, plus all racquet owners can upgrade to natural gut strings for an additional fee.