If you are looking for business ideas, how about you don't invent something new, how about you just improve something that already 'works'?
Can you take a product or service and make it bigger, smaller, lighter, longer lasting, easier to use, more convenient, quieter, more colourful, better supported?
Find something, improve it.
(I've said I can help with this (below), and I can, but you'll have to come up with the thing that needs improving, unless it's your own product/service. It should be something within your world, and I'm unlikely to know who you buy from.)
Get it done by: http://www.johnallsopp.com
For: .. depends