Since I have never understood the point of these challenges ( no criticism of you at all here), let me explore a few things with you
1. If its a personal challenge, why not set it for yourself and do it anyways? what does particiaption by others add? Its like, when I was in school, folks would go for 'joint study'. I never understood the concept. If I study, I study, if I dont, i dont. How can i be helped or harmed by other people studying.
that's fine Ujjwal - it may well be that the format isn't right for you - not everyone is the same, and some peoples ability to self motivate is not as strong as others. For the school stuff - personally I needed a darkened room, a good reading light over the desk I was working at, and a large supply of high caffeine drinks to tide me over
2. If you want to try something you dont normally do - isn't the easiest thing to do is to go out and try it. Of course you could ask for ideas and feedback - but what does other people doing or not doing it add to the process.
The hardest thing i find is actually coming up with a subject to work to. Letting someone else set the topic allows me to "work to a brief" much as I would if working for a client. It also seems to be a relentless way of finding great gaping holes in my abilities - much as this years POTY competition has done - High Speed Photography - Cross Processing - and of course this months Street - have all been topics that I've had to step outside of my realms of experience and comfort. Some i've enjoyed, a couple i've actually hated - but none of which i'd have actually picked as something to do for myself. I have actually learned something from every months challenge though, which is the intention of this years POTY competition. I've also shot as much as I could on film - though it wasn't always well recieved.
To me, either its a competition where everyone competes and there is a winner ( however he is chosen); or its a personal journey, where no one else matters.
Not criticising your idea at all, just trying to understand a different point of view