NEMO has a few small datafiles in the directory $NEMO/data, so there is no need to download extra files. In addition, data can be easily created on the fly. See below for an example.
Generate your own data
In general it is easy to generate data from NEMO. Here is an example to print the phase space coordinated of a 10-body Plummer sphere using snapprint
$ mkplummer - 10 seed=123 | snapprint -
### nemo Debug Info: x y z vx vy vz
-0.609486 -0.221687 -0.450963 -0.0766784 -0.209397 0.396561
4.80925 -0.486182 -1.52575 0.418474 0.117766 0.230193
0.545314 0.0795464 0.0632245 0.0867019 -0.109128 -0.282036
0.377209 -0.213318 -0.011833 -0.739982 0.649302 -0.0595349
-0.0724005 0.706104 0.0899005 0.158021 0.0702185 0.316083
-0.561212 -0.32416 1.18761 0.379356 0.257397 0.0247723
-0.312291 -0.902718 -0.451821 0.669557 -0.463708 -0.117066
0.36967 0.154617 0.681866 -0.0283658 -0.0937881 -0.135925
0.106249 0.255479 -0.0102538 -0.757828 0.0154417 -0.328447
-4.6523 0.95232 0.428016 -0.109256 -0.234103 -0.0446015