With the Intense Training perk, a single point can be put into any S.P.E.C.I.A.L. attribute. Each point will be fundamentally identical to a point that had been allotted during character creation, and so will allow the player character to gain more implants (Fallout: New Vegas) or perks.
It is similar to the Gain perk from Fallout 2, except that the bonus stat point can be spent wherever desired and this perk is available at level 2 instead of level 12.
In Fallout 3, taking this perk at level 2 to increase Intelligence by 1 gives the player 18 more skill points by max level (28 points with Broken Steel installed), which is considerably more useful than any of the skill-raising perks available at that level.