<p>I'm writing a Rails application, but can't seem to find how to do relative time, i.e. if given a certain Time class, it can calculate "30 seconds ago" or "2 days ago" or if it's longer than a month "9/1/2008", etc.</p>

You can use the arithmetic operators to do relative time.
```
```
Time.now - 2.days
```
```
Will give you 2 days ago.