Ricardo Bittencourt created a patch for the Pack-In Video game Rambo. He felt it was a shame that this great game had only a simple monochrome titlescreen. He created an improved titlescreen and, in order to keep within the 16kB RAM limits and 32kB ROM limits of the original game, an impressive image compression routine to make things work. On his website you can find a patch to update your ROM image and extra information on the compression routine he used.
Relevant link: Rambo Plus website