At least 1: Hunting Grounds. It was when Spiral kidnapped Kurt [Nightcrawler] and Wanda [Scarlet Witch] for her master's dangerous game show [Mojo's Hunting Grounds!].
There are 26 episodes in total of season 1, we don't yet know if there will be a season 2.
Sadly, there will not be one... sad because Nightcrawler and Scarlet Witch never officially got together... :'(
The original British version had 7 episodes during Season 1. The American version had 13 episodes during Season 1.
Never as far as anyone knows unles the creator decides he wants more episodes
There are 28 episodes during Season 3 of Wizards of Waverly Place.
There was only one season of Wolverine and the X-Men
The season was shortened to 20 episodes due to the writer's strike that occurred during the production of Season 7 of Smallville.
Season 1 - 23 episodes Season 2 - 24 episodes Season 3 - 23 episodes Season 4 - 17 episodes Season 5 - 24 episodes
20 episodes in the 1st season of bleach, 21 episodes in the 2nd season of bleach, 22 episodes in the 3rd season of bleach, 28 episodes in the 4th season of bleach, 18 episodes in the 5th season of bleach, 22 episodes in the 6th season of bleach, 20 episodes in the 7th season of bleach, 13 episodes in the 8th season of bleach, 22 episodes in the 9th season of bleach, 16 episodes in the 10th season of bleach, 7 epidoes in the 11th season of bleach, 17 episodes in the 12th season of bleach, 21 episodes in the 13th season of bleach!
According to Wikipedia, there are 18 episodes in Season 5 of "One Tree Hill."
The number of episodes per year for Law and Order SVU, the only L&O series still filming, are as follows: season 1, 22 episodes season 2, 21 episodes season 3, 23 episodes season 4, 24 episodes season 5, 25 episodes season 6, 23 episodes season 7, 22 episodes season 8, 22 episodes season 9, 19 episodes season 10, 22 episodes season 11, 24 episodes season 12, 24 episodes season 13, incomplete
Season 1: 20 episodes Season 2: 20 episodes Season 3: 8 episodes