Give me a project idea ..

hello guys i am bored of the work .

i want to do a project which will engage me and let me learn new things.

i have done several projects in software(Android, java, php, .net, many more languages),microprocessors (arduino).


so i am looking for some project which will be useful for people in general and can be done by one person (in weekend) within 3 months.


please suggest me some good project (innovative new not same old ) idea to go with like some apps which you want but there isn't any available online or any other idea .

also if anyone is interested to collaborate with the project with me they are more than welcome.
:):):):):):)