In an age of stringent airport security and fewer flights to Narnia, theater remains the easiest and most rewarding way to be transported to new worlds while seated in a row of cushioned chairs. Today's Groupon invites you to one of 24 performances of Green Whales at Unicorn Theatre. For $15, you get one ticket to a Friday- or Saturday-night show at 8 p.m. (a $32.50 value). You can also get a ticket to a Sunday matinee at 3 p.m.; a Tuesday-, Wednesday-, or Thursday-night show at 7:30 p.m.; or the one-time Saturday matinee on March 6 at 3 p.m. for $12 (a $27.50 value). Shows start with the previews on March 3 and 4 and run through closing day on March 28. Once you receive your Groupon, call the theater's box office to schedule the date you would like to attend.