How do I set the color and font in a RichEditBox

You use the SelectionFont and SelectionColor properties. Make sure the control had focus. Then the following code will set the currently selected text to a red-bold-courier font. If no text is currently selected, then any new text typed (or inserted) will be red-bold-courier.

[C#]
	richTextBox1.Focus();
	richTextBox1.SelectionColor = Color.Red;
	richTextBox1.SelectionFont = new Font ('Courier', 10, FontStyle.Bold);

[VB.NET]
	richTextBox1.Focus()
	richTextBox1.SelectionColor = Color.Red
	richTextBox1.SelectionFont = new Font ('Courier', 10, FontStyle.Bold)