Sega and Nintendo have since collaborated on various software titles. Sega has developed a bi-annual Mario & Sonic at the Olympics series of sports games based on the Summer and Winter Olympics since 2008 featuring characters from both the Super Mario and Sonic series,[42] while Nintendo has developed the Super Smash Bros. crossover fighter series for numerous Nintendo properties that has included Sonic as a playable character along with other Sonic characters in supporting roles since Super Smash Bros. Brawl.[43]