© I FARTlek when I Run - Funny Fartlek Slogan. Fartlek - a running training regimen that sometimes gets the giggles because of its name! A Great typography Gift for People who Run. A Variety of Runners like to Fartlek - such as Cross Country, Half Marathoners, 5k, 10k, 26.2 milers, Track and Field Athletes and more! A humorous Running saying, original creator of quote. Some think Fartlek is a Pun, but it's a real thing.