Just a little demo of using a shader and renderTexture to make a stupid starwipe gag.
press UP to starWipe in press DOWN to starWipe out
gag reference https://www.youtube.com/watch?v=72bUheqRE5o
useful video (not mine) on the general concept https://www.youtube.com/watch?v=ZuV9Xlt-l6g&feature=related
starter shader i used (i added a color overlay to get that thick white border on the star) http://wiki.unity3d.com/index.php?title=Texture_Mask
ideas to make this fancier: animate the texture sizes so that the star "expands" instead of scaling it up (this would allow you to "cut" to your star camera more seamlessly instead of staying on the renderTexture)
just have a script that takes two cameras and a 0-1 slider value and starwipes between the two cameras (not sure if this achievable w/o RenderTextures ATM)