combine results from two queries and order by created_at? [rails 3]

Looking for a simple method utilizing active record to grab data from two models, combine the data, and then sort the combined output by created_at.

For example:

assume two models, Comment & Like both belongs_to User

return a combined list of @user's comments and likes sorted by date

I know I can do this in SQL but I'd really like an active record solution.

Thanks!