Capacitors and methods of forming capacitors are described. According to one implementation, a capacitor opening is formed over a substrate node location. Electrically conductive material is subsequently formed within the capacitor opening and makes an electrical connection with the node location. A protuberant insulative structure is formed within the capacitor opening and includes a lateral outer surface at least a portion of which is supported by and extends elevationally below adjacent conductive material. First and second capacitor plates and a dielectric layer therebetween are formed within the capacitor opening and supported by the protuberant structure. In one aspect, the conductive material is formed to occupy less than all of the capacitor opening and to leave a void therewithin, with the protuberant structure substantially, if not completely filling in the void. In another aspect, the conductive material is formed to occupy less than all of the capacitor opening and to leave a void therewithin, with the protuberant structure only partially filling in the void to provide a tubular structure.