On average, how many friends would I need to have to have at least one friend's birthday every day?
7000
Expected time to roll all 1 through 6 on a die
156067
Birthday problem, want about using unordered counting?
32170
Birthday Problem: How am I wrong?
155654
Is starting a group with 5 newbies (DM included) possible?
135166
How do I create a random post that will last for a day
79493
Probability of 3 people in a room of 30 having the same birthday
31285
What are the minimum contributions required for co-authorship
54493
Allow new users to comment for X times in a day
39037
How many close votes do I actually have each day?
128124
Is it unlikely to get the same number of heads/tails?
117162
How many ways can the 10 A's be distributed?
40741
What is the difference between "everyday" and "every day"?
147186
How many eggs can one eat per day?
52525
Limit the number of suggested edits that a user can make in a day
106469
Friend or Friends in this sentence
131737
Limit only one entry per day per user in sharepoint list
138601
There are $2n+1$ people. For each $n$ people there is somebody who is friend with each of them. Prove there is a "know-them-all" person.