Riding on animated tower shield

[With a box]

Like a hovering surf board.
1. Can I do that?
2. How fast a animated shield is?

[Tvtyrant]

1. If it were attached to a very large creature and you were very small, probably.
2. As fast as the creature it is attached to.

[Grod_The_Giant]

Depends. Are we talking about the Animated armor enhancement, or a tower shield that's been hit by Animate Object?

[Uncle Pine]

1. Yes, you can!
2. An animated +1 shield (as per the armor enhancement) has no movement speed. Instead, it floats within 2 ft. of the wielder, so it would take quite a lot of shenanigans to use it as a board.
An animated shield (as per the spell) has a 30 ft. speed, but can't fly so you cannot use it a la Silver Surfer.
A flying +1 shield (as per the flying weapon enhancement from Magic of Faerun) acts as an animated object, but has a 30 ft. fly speed.

Obligatory reference to Darrin's Magic Carpet of Flying Forcewall (http://www.giantitp.com/forums/showsinglepost.php?p=10294124&postcount=5). Just be sure to use a Tiny riverine buckler to save some bucks.

[Hrugner]

1. Yes, you can!
2. An animated +1 shield (as per the armor enhancement) has no movement speed. Instead, it floats within 2 ft. of the wielder, so it would take quite a lot of shenanigans to use it as a board.
An animated shield (as per the spell) has a 30 ft. speed, but can't fly so you cannot use it a la Silver Surfer.
A flying +1 shield (as per the flying weapon enhancement from Magic of Faerun) acts as an animated object, but has a 30 ft. fly speed.

Obligatory reference to Darrin's Magic Carpet of Flying Forcewall (http://www.giantitp.com/forums/showsinglepost.php?p=10294124&postcount=5). Just be sure to use a Tiny riverine buckler to save some bucks.

so just have an animated tower shield and hand it off to your invisible flying familiar and ride that?

[Uncle Pine]

so just have an animated tower shield and hand it off to your invisible flying familiar and ride that?

An animated (as per the armor enhancement) shield floats protecting the wielder as if she were using it herself, so it's probably not intended to stay horizontal as a board. I suppose you could perch on it if you were small enough, but it's not the same.
A +1 flying shield is slightly more expensive (~8.000 gp compared to ~4.000 gp for a +1 animated shield), but it better suits the OP's needs.

[Hrugner]

It stays near you as if you were wielding it, but you could be wielding it as if providing full cover from one direction. Have the familiar choose "up" and that should all work out. Right?

[Uncle Pine]

It stays near you as if you were wielding it, but you could be wielding it as if providing full cover from one direction. Have the familiar choose "up" and that should all work out. Right?

Technically? Yes. From a practical point of view that also accounts for coolness factors? Less so.