<p>How do I find the start of the week (both Sunday and Monday) knowing just the current time in C#?</p>

<p>Something like:</p>

<pre><code>DateTime.Now.StartWeek(Monday);
</code></pre>

This would give you the preceding Sunday (I think):
```
```
DateTime t = DateTime.Now;
t -= new TimeSpan ((int) t.DayOfWeek, 0, 0, 0);
```
```