It is a special weekend-only playlist when if you win you get two exp. instead of one.
You can not dual wield energy swords in halo 3 but there are rumors that you can in halo reach.
Yes.
Grifball is a Double EXP Weekend playlist on Halo 3 matchmaking. It resembles football, but with bombs, swords, and Gravity Hammers! Grifball can be played in Halo 3's online multiplayer whenever it is featured as a Double EXP Weekend playlist.
yes you can
I expect Bungie to keep the extras from halo 3 and move them to reach. So, to answer your question yes I think they will have double exp. weekend in reach.
halo 3 obviously
Halo 3: ODST is the newest of the two, but not the newest Halo game.
The halo time line goes Halo Wars, Halo: Reach, Halo:CE (halo 1), Halo 2, Halo: ODST, Halo 3. Halo 3 and ODST are practically at the same time.
Halo 3 ODST is not for PC but Halo 1 and maybe Halo 2-3 are
After Halo 3 there was halo wars, halo 3 ODST, and Halo reach. A new company (not Bungie) will be making a Halo 4 and rumor has it there will be a remake of Halo Combat Evolved.
it goes halo, halo 2, halo 3, halo 3 odst and soon halo reach will be available
Halo Games: 1. Halo: Combat Evolved (Xbox, PC) 2. Halo 2 (Xbox, PC) 3. Halo 2 Muliplayer Map Pack (Xbox) 4. Halo Triple Pack (Xbox) 5. Halo 3 (Xbox 360) 6. Halo 3 O.D.S.T (Xbox 360) 7. Halo reach (Xbox 30) Other Halo Games: 1. Halo Zero (PC) 2. Halo: Custom Edition (PC) Future Games: 1. Halo Wars (Xbox 360) 2. Halo: Chronicles (Xbox 360) 3. Halo 3: Recon (Xbox 360)4. Halo 3: ODST (Xbox 360)