During several years Codeforces users created useful userscripts that collected significant amount of fans. Tonight I merged a couple of popular scripts into one Chrome extension Codeforces Enhancer.
Brief description of features:
Colorize standings by used programming language
Multiple rating graph comparing
Hiding solved problems in the Problemset
You can download the extension at the Chrome Web Store: https://chrome.google.com/webstore/detail/codeforces-enhancer/ocmandagmgmkcplckgnfgaokpgkfenmp.
Source code on Github: https://github.com/agul/cf-enhancer.
I will be happy to receive feedback and suggestions :)
UPD (25.06.2015): Now on Results page number of unsuccessful attempts is shown near submission time.
UPD (25.06.2015): Latest version on Github (if unable to download from Web Store): https://github.com/agul/cf-enhancer/releases/latest.
UPD (27.07.2015): Options page added: now you can enable only functions that you like.
UPD (22.07.2020): Fixed HTTPS issue. Changed color scheme in Standings, similar programming languages are group by the same style. Latest version is available on Github.