The following Plurk CSS code can be used to modify the dropdown box; you see it when clicking the down arrow on a plurker's nick (in a plurk/plurk response).

Change the colors to those you like :) also, you may wish to remove this line "opacity: 0.9; /* see-through */" it is used to make the dropdown see-through.

A nice color table http://www.colchis.com/clrtable.html

Have fun.

(also i made the box bigger/text bigger to go with my BIG plurk text for the 24in screen)

/* start of the drop down box */

/* make the box/font bigger */
.AmiMenu.info_menu td
{
padding:0;
width:305px;
overflow:
hidden;
font-family: Arial, Helvetica, sans-serif;
font-size:14px;
font-style: Normal;
line-height:20px;
color:#fff;
cursor:pointer;
}

/* change the color to blue/round the box */
.AmiMenu.info_menu
{
background-color:#0174DF; /* blue */
border:5px solid #0174DF;
border-right:5px solid #0174DF;
border-bottom:5px solid #0174DF;
margin:10;z-index:10000;
-moz-border-radius: 10px; /* rounded */
-webkit-border-radius: 10px;
opacity: 0.9; /* see through */
}

/*make the avatar pic bigger */
.AmiMenu.info_menu .user_info img
{
padding:0 0px;
width:55px;
height:55px;
border:0;
position:relative;
right: 10px;
}

/* change the color when cursor is over the user info */
.AmiMenu.info_menu .user_info.on
{
color:#FFFFFF;
background-color:#FF0000;
cursor:default;
}

/* change the highlight color */
.AmiMenu.info_menu .on
{
background-color:#6A5ACD;
border:none!important;
margin:0!important;
}

/* change the block plurker color */
.AmiMenu.info_menu .block
{
background-color:#000;
color:#FFFFFF;
}



.AmiMenu.info_menu .separator{
background:url(http://static.plurk.com/static/emoticons/silver/dance.gif) repeat-x 0 bottom;
height:30px;
padding-top:6px;
}


/* end drop down box */


P.S.
I'll let u figure where to put this code:

/info_list/separator.png

ROFL