Doodle is just perfect for addressing this problem.
With Doodle it's as easy as possible to find an appropriate date and time suitable for everyone:
First, someone has to create multiple possible dates and times, for example from Monday to Friday next week - each day from 8 to 10 AM, from 10 to 12 AM, from 2 to 4 PM and from 4 to 6 PM. Therefore Doodle offers a calendar where one can select the days that coming question. Furthermore, if one has entered the time frames for one day, these frames can be copied for the other days so one does not have to enter the same time frames manually for each day.
Next, the other members have to be invited. They can be invited via the link to this survey, for example one can send the link to each member via e-mail.
Then, each member has to vote, that means everyone has to check the suitable dates and time frames. For example, person A has only time on Monday and Friday from 8 to 12 AM and therefore only checks these four options.
If everyone has voted, one can see the summary beneath each date / time frame connection. For example, 8 persons have time on Monday from 8 to 10 AM, 6 persons from 10 to 12 AM, and so on. The dates and time frames where most people have time are marked bold, so it's very easy to quickly to filter the best date / time frame connections.
Furthermore, Doodle also supports time zones, hidden surveys, limited options and more. It also offers an adapted version for mobile devices.