Indeed answers any closed question, a sarcastic remark or general remark you really don't care to comment on. In the case of open questions replying "indeed" lets someone know that you really don't give a flying pig's ass and can express surprise, skepticism, or irony.
Definetley one for your vocabulary.
Be warned, the use of indeed may cause some people to feel uncomfortable and less superior in the users presence, intimidated by their free usage of the word.
We did indeed.
Have you finished your algebra homework from section 9.4?
<Teacher:> Do your Maths sheet!
<Mother:> Where did you put your sports shoes?