I am shocked at the lack of Tokusatsu knowledge so I will go on a spree:
Tokusatsu is the greatest form of entertainment known to man. If you've never heard of, or watched any, then I suggest you head to www.tvnihon.com
and to the torrents section and get Kamen Rider Kabuto. It's a good series to start, since it starts out awesome, unlike other series that take time to build. After you have watched a bunch of episodes from it, perhaps you might want to branch of to another series. There are both more serious and more light-hearted series, as well as altogether different ones. Do not judge them solely due to your prejudice against Power Rangers.