Throughout Dragon Ball/Z/GT, there are tournaments held every-so-often: Budoukai. This section was created to explain them, and their results.
The 21st Tenkaichi Budoukai:
Champion: Kame Sennin.
Other Contestants: Bacterian, Grandpa Gohan, Guilan, Jackie Chun, Karin, Kuririn, Lanfan, Nam, Tao Pai Pai, Yamucha.
The 22nd Tenkaichi Budoukai:
Other Contestants: Chaozu, Cymbal, Jackie Chun, Kuririn, Pam Put, Piccolo Daimaou, Wolf Man, Yajirobe, Yamucha.
The 23rd Tenkaichi Budoukai:
Other Contestants: Chi-Chi, Kuririn, Shen, Tao Pai Pai, Tenshinhan, Yamucha.
The Cell Games:
Other Contestants: Gokou, Mr. Satan.
The 24th Tenkaichi Budoukai:
Champion: Mr. Satan.
Champions: Gokou, Paikuhan(draw).
Other Contests: Aqua, Frog, Maraikoo, Tapikae, (more).
The 25th Tenkaichi Budoukai:
Adult Division Champion: Mr. Satan.
Adult Division Runner-up: Android 18.
Other Contestants: Gokou, Great SaiyaMan, Jewel, Kaioshin, Kibito, Killa, Kuririn, Ma Junior, Mighty Mask, Pintar, Spopovitch, Videl, Yamu.
Children Division Champion: Chibi Trunks.
Children Division Runner-up: Goten.
26-28th Tenkaichi Budoukai:
Champion: Mr. Satan
Runner-up: Fat Buu
Note: Mr. Satan cheats by allowing Buu to defeat all of the other contestants first, and then having Buu throw him the match.
Information provided by Masenko-Ha.com (owned by DBZN staff member Madd Skittle).