Just sharing whatever I read online about 2012 features:-

1) contained database

Need to enable this at server level using sp_configure

This database as of now have option to be configured with 2 option. Null and partial. Third option "Full" will be in future release.

2) restore database with timeline

This one is going to be best as now its fully graphical and you can scroll till the point you want to restore.

3) alwayson

Cant remember the exact word I read somewhere, but the meaning was somewhat similar to this:-

Alwayson is the first child of successful marriage of Cluster and mirroring.

4) one good t-sql functionality I liked is "Format". this is really helpful in converting the datetime to local format.

5) Server Level role can be created but the permissions are pre-defined which you have to select from the list. You cant have your own customized permission in this customized role.

I am sure there are lots. Just sharing whatever I know about 2012 and trying to correct and add more in my 2012 KB.