For my friends at work (or not) on their dissertations, I found this article on the 43folders blog with some great ways to overcome writer block. It is more than a few years old, but I imagine the techniques still work today.
I'm finding all sorts of great ways to waste time and procrasinate the inevitable work on my dissertation. Here's a list, in no particular order, of my recent time wasters that you may enjoy, too:
Write a blog
We use TypePad as our blogging service for both Innovate Learning's blog and this blog. You can get a free membership to TypePad (as well as many of the other blogging services), but we make use of the custom templates, including the ability for inserting header banners like the ones you see at the top of each of our blogs, not to mention the great ability to publicize your blog available with our around $15/month (at the time of this writing) membership.
Edit a photo
Many people store their photos on an online sharing system such as Flickr. However, there are limited photo editing options available on those sites and most of us don't have the patience to learn Photoshop. Try Picnik as a great means to edit your photos for free online. It is incredibly easy to use. Upload your photo, or link your account to be able to access the photos you already have stored in an online service, such as Flickr. Then you can change the coloring, remove red eye, crop, resize, place text, and add frames around the photo. All our banners and photos that you see at the top of our blog postings were done using Picnik. While it is a time waster, in terms of avoiding working on my dissertation, it is an efficient tool that saves time over when I used to do stuff in Photoshop and other photo editing programs.
Feed the hungry
Free Rice helps you feed the hungry in other countries, while you show off how much stuff you know by answering questions.
Use Slate.com's Career-Specific Time Wasting Advice
These tricks should get you started on wasting your time, but if you want advice that is specific to your vocation, check out this advice from Slate.com.
Best wishes in your procrastination.