Instapaper provides a read-later bookmarklet, and using that, a series of web-pages can be made into an ebook fairly easily. Instapaper gives download options in epub, mobi and "printable" (from which one can print to pdf). The thing to note is that the page you want as the first page of your ebook should be the last you click "Read later" on. That is to say, last in first out. So, you have to click "Read later" on the last page of your ebook first, and go on to the beginning, and then export from instapaper.