Is halo 3 and halo 3:odst the same thing?

[Misty]

My Boyfriend wants halo 3 for Christmas and every where i look i see halo 3 and halo 3dst. I was wondering if they are the same thing or is there a difference between the 2. i don't play video games that much so i really don't know. I asked my bro and his friends and they told me that they are the same thing but i want to make sure first before i buy it and find out they are 2 totally different things.

 

[Ben]

Two different games both of which set in the same universe, location, time etc..
Halo 3 is the last in a trilogy of games following a single characters experience.
Halo 3: ODST is focused on telling the story of a group of marines caught in a battle for a city.

To find which version he wants ask his mates or try and bring it into a random conversation 0_o

 

[el nino]

ive heard that the campaign is about 3 hours long

 

[TwinTipZ]

There is a big difference. If he wants Halo 3 and just Halo 3, get him Halo 3.