For today only, not sure which time zone, but Mount & Blade Collection is $8.47 USD from Steam. Save 75% from purchasing the games idividually.
Mount & Blade
Released 4 Nov 2008
-75% $14.99
$3.74
Mount & Blade: Warband
Released 1 Apr 2010
-75% $19.99
$4.99
Mount & Blade: Warband - Napoleonic Wars
Released 20 Apr 2012
-50% $9.99
$4.99
Mount & Blade: With Fire & Sword
Released 4 May 2011
-75% $9.99
$2.49
This whole series' multiplayer really gets the adrenaline flowing, especially in melee!