Google Talk Guru is an experimental service that allows you to get information such as weather forecasts, sports update, currency conversion, definitions, etc via chat.
To use this service, you first need to send a chat invite to this address: guru@googlelabs.com.
Once your invite gets accepted – almost instantly – you can start sending your queries by finding ‘Guru’ in your contact list.
Example Queries:
Google Talk Guru works on any client or device which supports Google Talk. You can even send your queries inside Gmail.