Marvel Comics API
While having access at all is nice, the terms of use are prohibitive and somewhat heavy handed.  They basically say you can make something, but can't charge for it in any way, you can't create a mash-up (no augmentation of data) and if it works out, Marvel will probably implement it for themselves anyway. Not really as 'open' as you might hope.The following default rules apply to all Apps:Advertising. No advertising or sponsorship of any kind may appear on or be associated with any App (unless included in the Content made available by Marvel).No Charge. All Apps must be offered free of charge to download or otherwise access and may not contain any in-App purchase features or any other method of monetization, unless approved in writing by Marvel pursuant to a separate written agreement as described below....NO PRESS RELEASES. You may not issue any press release or make any public statement about the Marvel API (and related Content), Tools, the inclusion of any of the foregoing in any Apps (yours or others') or these API Terms of Use without Marvel's prior written approval....Use of our Content. You may not change or edit the Content (e.g., modify, augment)....You understand and acknowledge that Marvel may be independently creating applications, content and other products or services that may be similar to or competitive with your App, and nothing in these API Terms of Use will be construed as restricting or preventing Marvel from creating and fully exploiting such applications, content and other products or services now or in the future, without any obligation to you.