I would invest my bitcoins in an offline or real world kind of business. The only problem I see is that bitcoin is still not well known and that when investing it in the real world no one will accept it yet. So probably if you intend to do this, you have to convert your bitcoins to fiat first so that you can buy what you need for the investment.
Cause that one problem you will lose your investment, how do you plan to work and earn if you do not have customers? Is there any offline business that accepts just bitcoin, I do not think there is, they accept local currency and on a side they accept bitcoin, probably cause boss knows about bitcoin. There are countries with many bitcoin users and in this countries you can start some offline business, but for example in my little city it would be pointless. Choosing the good spot for your business is important, therefore bitcoin offline business can exist just in some cities for now.