Creatures must react to danger with a "fight or flight" reaction, which means either boxing their opponent or commandeering a nearby blimp. Hone your martial instincts with today's Groupon to Defend U LLC. Check the site for the full schedule. Choose between the following options:

• For $25, you get four drop-in classes (a $60 value).
• For $50, you get eight drop-in classes (a $120 value).

Featuring mixed-martial-arts classes with an emphasis on self-protection, Defend U students ages 3 to adult study Brazilian jiu-jitsu, kickboxing, and American kenpo under the guidance of skilled instructors. The varied schedule of rotating classes is divided into age groups, ensuring proper safety and instruction. Defend U keeps pupils engaged in disciplines such as kenpo karate, which emphasizes power, speed, and accuracy while teaching attack-evasion techniques such as blocking and diverting attention with street magic. The Grappling/Grappling Defense class, a technique popularized by the UFC, teaches apprentices to stay on their feet if an attacker tries to knock them to the ground. At the Stick and Knife Defense class, students learn how to defend against an attacker wielding a weapon, such as a blade, scissors, rock, or paper. Yoga classes are also offered to increase students' flexibility and concentration while relieving stress.

At Defend U, students can kick, punch, and pummel surly heavy bags or Wavemaster water bags while bounding across 2,100 square feet of 3-inch mats on a foam floor base. Plenty of sparring equipment remains on clenched fist for use during class, including sticks, shields, and focus mitts, which are embedded with mini televisions to keep an opponent's attention. Clean lockers rooms complete with showers are also on-site for both men and women.