Let $S$ be a closed surface embedded in $\mathbb{R}^3$, let's say of genus zero. I seek examples of $S$ with the following property: If one selects a random point $p$ on $S$, and a random direction $u$ tangent to $S$ at $p$, then the geodesic issuing from $p$ in direction $u$ is a closed geodesic with positive probability. I know this is trivially true for Zoll surfaces, on which *every* geodesic is closed. But are there non-Zoll $S$ where geodesics are prevalent enough to yield a positive probability (perhaps $1$)? <br /> ![ZollDiscr][1] <br /> <sub>(Zoll Surface: Image from [Polthier&Schmies][2] via [this MO question][3])</sub> [1]: https://i.sstatic.net/rCTNz.gif [2]: http://www-sfb288.math.tu-berlin.de/Research/GEODESICS/Geodesic.html [3]: http://mathoverflow.net/a/150564/6094