This is getting rough... The Star Wars prequels were one thing, and Hollywood has always loved remakes. But this latest fascination with doing sequels of movie franchises long abandoned is getting silly. If you want to read an article, read this one.
Otherwise, i think this list speaks for itself. This is all the sequels that have come out in the last year or are slated to be released in the near future (or known/planned movies in the more distant future). That's right, from 2005 forward, we will be or have been subjected to 54 sequels.
(OK, i just found another page with many more listed. I will work to add those to the list in the near future)
Of course many of these actually reference TV shows, comic books, or novels that far pre-date even the first movie in the series. I also don't count movies that are straight remakes. It would have taken me forever to put that list together.
I guess there really is nothing new in Hollywood.