After the category title (and explanation if applicable), it says in bold 'Total questions ...' This is rounded up to the nearest hundred.
The only real way to find out is to select a category, find out how many pages there are, and multiply the number of pages by the number of questions displayed per page (the default is 50 questions per page).
You can find the most amusing questions in the 'Most Amusing questions ever asked on WikiAnswers' category. There is an entire category dedicated to amusing questions. Search for that category when you click the 'browse our ... categories' on the home page, and you should find that category.
We have a category for the Olympics. That category has many sub-categories. Take a look around the category and pick questions you can answer.
You can find unanswered questions about Neptune in the Planet Neptune category: Special:UnAnsweredQ
Click "Browse Categories" on the left under Site Tools, and then search for an Animal Category. In that category, click "Unanswered questions" and you will be taken to a list of all the Unanswered questions in that category.
You can answer all questions. You just have to find out what category they are in, and Answer away!
Yes, when you go to a category at the top of the page under the category title you will see the total number of questions in that category.
There is no automatic way to take you to the oldest of the questions in the Uncategorized category. To see all the questions in the Uncategorized category, click on the Related link.
It's different for every category, you can find all of the most discussed questions when click on a particular category, once there, scroll down and the list starts from the first one down to however many there are.
As if 8:34PM EDT on 5/2/11 there where 158,700 questions in the Movies category.
Every category have 2 sections called "All unanswered questions" and "New questions". That is where you find them.
You can search if there are sufficient questions on the category you are good in, in wikianswers. If you find atleast a 50 questions, you can request an y of the supervisors to help you form a new subcategory for that topic. You can also press the *NEW QUESTIONS* button next to unanswered questions which has a mix of many different topics!