Game is available here.

Serious Sam 4 is out. Launch Trailer: here

Serious Sam 4 won't come out this August, new date is September 24. Trailer

Serious Sam 4 videos

It's finally here

On E3 this year Croteam announced Serious Sam VR: The Last Hope. The game will be VR only and coming this summer with early access.
Steam page
Trailer
Interview

Serious Sam 3 has been updated with some holiday fun for a limited time. More information here.

Serious Sam Humble is purchasable for a week. Contains SSHD,SSTRE,SSDD,SSKA and also the second public test of the first game. Even more if you pay more than the avarage you get SS2 and SS3 too.
All funds to Croteam will go towards making the upcoming Serious Sam 4 which hopefully coming in 2014.

Serious Sam Double D XXL is available on xbox360.
Coop trailer | Gun diary 1 trailer | Gun diary 2 trailer | Megjelenési trailer