Is this a weed?

I just moved into this place and near the front door there are many of these plants. They aren't anything I've ever seen before so I was wondering if it was a weed or if I could grow it indoors.
Thanks.

 

Yes to both questions! It's a Bryophyllum daigremontianum (aka Kalanchoe)

 

I believe it's Kalanchoe houghtonii, (recently renamed & given species status) similar to the Bryo mentioned (Mother of Thousands). Many consider it a weed. Some (like me) grow it as carefully confined as possible! The babies grow in cracks of cement driveways, if that gives you an idea. They like to hitchhike in nearby pots!

 

Yes, my definition of a weed is a plant that you didnot plant or is growing out of control.

 

Thanks a lot for the replies. And yes it is growing out of control in the cracks of my sidewalk and the cracks of my siding. It is rather different than what I'm used to seeing grow freely.