Write a program that says how many times it was ran
Somewhat less trivial example than y'old bash, in C:

#include &lt;stdio.h&gt;

int main(int argc,char **argv){
    const char *data="Da best marker in da world 0\0\0\0\0\0\0";
    FILE *f;
    int i;
    char c;
    long int pos;
    printf("%s\n",data+27);
    f=fopen(argv[0],"r+b");
    i=0;
    c=fgetc(f);
    while(!feof(f)){
        if(data[i]==c){
            i++;
            if(i==27)break;
        } else i=0;
        c=fgetc(f);
    }
    if(i!=27)return 1;
    i=0;
    pos=ftell(f);
    c=fgetc(f);
    while(c!='\0'){
        i=10*i+c-'0';
        c=fgetc(f);
    }
    i++; //The increment!
    fseek(f,pos,SEEK_SET);
    fprintf(f,"%d",i);
    fflush(f);
    fclose(f);
    return 0;
}