Coming in at a whopping 223(!) characters, a first attempt:

for(0..$#_){if($_[$_]=~/X/){$t+=10+($_[$_+1]=~/X/?10:$_[$_+1])+($_[$_+
+2]=~/X/?10:($_[$_+2]=~/\//?10-$_[$_+1]:$_[$_+2]))}if($_[$_+1]=~/\//){
+$t+=10+($_[$_+2]=~/X/?10:$_[$_+2]);splice@_,$_+1,1;last if!defined$_[
+$_+2]}else{$t+=$_[$_]}}$t
[download]

There has to be a better way... I thought about switching the if-elsif-else to BLOCK,next if(EXPR);, but I couldn't figure a way to get rid of the splice in the elsif block. *shrugs*

Update: for(0..$#_){if($_[$_]=~/X/){$t+=10+($_[$_+1]=~/X/?10:$_[$_+1])+($_[$_+2]=~/X/?10:($_[$_+2]=~/\//?10-$_[$_+1]:$_[$_+2]));last if!defined$_[$_+3]}if($_[$_+1]=~/\//){$t+=10+($_[$_+2]=~/X/?10:$_[$_+2]);splice@_,$_+1,1;last if!defined$_[$_+2]}else{$t+=$_[$_]}}$t

That fixes the perfect score problem. Comes in at 242.

Update2: With some ideas from chipmunk, I'm down to 208. (I didn't want to steal his concept, but improve my own. *grins*)

@b=@_;sub X{pop=~X?10:pop}while(($_=shift@b)+1){$t+=10+X(($b[0])x2)+X(
+($b[1]=~/\//?10-$b[0]:$b[1]),$b[1])and(defined$b[2]||last)if/X/;if($b
+[0]=~m!/!){$t+=10+X(($b[1])x2)and(defined$b[2]||last)}else{$t+=$_}}$t
[download]

------
/me wants to be the brightest bulb in the chandelier!

Vote paco for President!

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.