Daily Shoot is a great site for those taking part in the 365 challenge!
If you are stuck with an idea for your daily photo head here to grab an idea. Each day there is an assignment based on a huge range of ideas. You can check out the website daily or follow them via twitter to see the assignment also.
What I love the most about the site is the easy integration between flickr and twitter to take part in the daily assignments. It's not another site that you have to sign up to and log in to each time you want to take part. Your image is easily linked through a quick process.
Once you have selected your image post your photo to flickr (or another twitter images sharing site). Then all that needs to happen is you send a tweet to @dailyshoot with the link and the assignment hashtag (#ds54 for assignment 54).
A few minutes later the image will be loaded up on The Daily Shoot front page... couldn't be easier. You can then also see how other people have interpreted the daily assignment and leave comments/feedback etc for them.
Give it a go... you can go back through the past assignments and take part in them when you have extra time or aren't feeling the assignment of the day!