Music should be performed outdoors whenever possible in order to encourage the stars to wave their lighters and keep cantankerous planets awake late into the night. Embrace atmospheric revelry with today's Groupon to Bluesfest International, held from July 15 to July 17. This Groupon is only valid for the festival in London. Choose between the following options:

• For $12, you get a one-day festival pass (a $30 value).
• For $25, you get a three-day festival pass (a $55 value).

The 12th Bluesfest International welcomes music mavens to the streets of London for three days of premier North American and European blues and rock performances. Guests stand or sit in self-supplied chairs for general-admission seating, requesting songs via cup phone from a stage-bound musical lineup on the corner of King and Clarence. Starting at 6 p.m. on Friday, ears taste nourishing notes from artists such as the one-man-band grassroots folkist Sweet Willie Tea and 1960s blues-rock outfit Ten Years After. Saturday audiences arrive for 4 p.m. doors to witness the genre fusing and guitar tickling of tunesmiths such as Smokin' Joe Kubek and Bnois King and Alto Reed's Motor City All Stars. Sunday's 3:30 p.m. doors invite international Girls with Guitars to sling their stringed silence smashers, and ex-Barenaked Ladies vocalist Steven Page concludes the festival with a late-night solo set and microphone-holding demonstration.

While attendees are prohibited from bringing their own alcohol, coolers, cameras, or security guards, fans can browse a wide range of local fare and beverages at large festival tents run by the city's restaurants.