Grant Opportunity: NLnet
The NLnet foundation gives grants of €5K-€50K to open source projects, aiming to stimulate "research and development in the domain of Internet technology".
The prefered instrument of NLnet are microgrants: small, independent projects supporting independent researchers and developers. NLnet can fund or co-fund various types of projects, such as software development or standards efforts. NLnet does not require so called 'matching' for projects and may decide to fund 100% of your project. For smaller projects there is a fast procedure which could have your project up and running in 6-9 weeks
The current call for proposals ends on 1st Dec and has a topic of "Next Generation Search and Discovery".
I was pointed to this by an employee of NLnet, Jos van den Oever. I don't immediately have any ideas to propose, but maybe it's interesting.