Father of the groom speech
Make it short and funny. Don't step on anyone's toes.
If your son is getting married and you are asked to do a Father of the Groom speech, you may find yourself initially a little taken aback. Traditionally, a Father of the Groom does not make a speech, that honour is usually bestowed upon the Father of the Bride, and so to begin with, you need to understand who else at the Wedding will be speaking. That will give you an idea of what type of ground it will be appropriate for you to cover, and what is best left to the others.
If there is also going to be a Father of the Bride speech, then you can be sure that that speech will be focused largely upon her, so you need your speech to focus mainly on the groom, perhaps also touching on their lives together up until the marriage. If there is also a Best Man speech, this is also likely to focus mainly on the groom and his life so far (perhaps including some activities you are unaware of!) so you need to make sure you that have a slightly different angle on the subject. Think about some fun tales from his childhood perhaps that only you, as his parent, would know about. Traditionally, the Father of the Bride will do any necessary thank-yous, (for example, to the bridesmaids) so you do not need to worry about that.
Anecdotes and stories illustrating the character of the Groom generally go down well. People will be expecting you, as his father, to be happy and emotional about the wedding, so don't be afraid to put some of that emotion into the speech. Above all, keep it relevant, light and concise as you are likely to be one (probably the first) of at least three people speaking, so don't drag it out or outstay your welcome.