So I've got a script that generates random "filler" from a database. But the generated list isn't random enough. Here's a sample output:

00:02:45 - Trailer: The Baby (1973) - URL for Item
00:02:36 - Burlesque: Jenny Lee - URL for Item
00:07:10 - Cartoon: It's a Greek Life - URL for Item
00:02:53 - Trailer: The Sinister Urge - URL for Item
00:00:60 - Short: Kevin Ryan - Coney Island Merman IPA - URL for Item
00:02:25 - Burlesque: Cherry Knight - URL for Item
00:03:06 - Burlesque: Chris LaChris - URL for Item
00:00:48 - Short: Save Free TV - URL for Item
00:08:33 - Cartoon: The Headless Horseman - URL for Item
00:01:46 - Trailer: Attack of the 50ft Woman - URL for Item
00:01:50 - Trailer: Fiend Without A Face - URL for Item
00:01:55 - Trailer: The Zombies of Mora Tau - URL for Item
00:03:33 - Short: Pipe Dream (2001) - URL for Item
00:06:56 - Cartoon: The Goose That Laid the Golden Egg - URL for Item
00:07:18 - Cartoon: The Henpecked Rooster - URL for Item
00:07:09 - Cartoon: It's Got Me Again - URL for Item
00:10:20 - Cartoon: Snails - URL for Item
00:00:11 - Short: Bizarre TV Advert Bumper - URL for Item
00:00:59 - Short: Kevin Ryan - Left Hand Milk Stout - URL for Item
00:02:19 - Short: Cats vs Zombies - URL for Item
00:00:39 - Commercial: Head Shrinker - URL for Item

It starts out fine, but then it starts to get "stuck" on a category (like Trailers or Cartoons).

Is there any way to stop it from choosing the same category twice in a row? Even better would be if it ran through a majority of the categories before duplicating one (it already doesn't duplicate actual entries).