Radio waves, like ghosts and KGB agents, make their presence felt while staying out of sight. Respect the invisible with today’s Groupon: for $25, you get a membership to Capital Public Radio, home of KXJZ 90.9 FM and KXPR 88.9 FM (up to a $120 value, based on an average general membership. Membership must be activated by May 16.

When not occupied taking home plaudits including Edward R. Murrow Awards for investigative reporting and ongoing feature coverage, Capital Public Radio's broadcasters operate a safe haven for jazz, classical music, and National Public Radio stalwarts. In addition to the good vibes that come with helping the station defray the cost associated with broadcasting quality programming, members are rewarded for their largess with a bevy of bonuses as part of the station's perks program. Keep up with Capital Public Radio goings-on with issues of the CPR Quarterly, or take advantage of discounted or free admission to station-sponsored community events such as the annual used record & CD sale. New members will also get their names dropped into a raffle for tickets to the December 3 performance of This American Life host and former New York Mets closer Ira Glass.